WATSONVILLE -- The European grapevine moth has been eradicated in Santa Cruz County, ending an 18-month quarantine in parts of Aptos and Watsonville.

Quarantines also have been lifted in Santa Clara and Nevada counties and a portion of Sonoma County, authorities announced Monday.

To ensure the moth doesn't pose a threat in the future, county agricultural officials will continue to set out traps and monitor grapes imported from quarantine areas elsewhere in the state, now limited to Napa County and adjoining portions of Solano and Sonoma counties.

Mary Lou Nicoletti, county agricultural commissioner, said cooperation among county, state and federal officials, growers, and residents led to ridding the area of the pest.

"All those pieces came together," she said. "It's good to have had some success."

The moth, first discovered in Napa in 2009, was initially mistaken for a common pest and left unchecked. Eventually, 100,000 moths were trapped in the wine-producing region.

Santa Cruz's infestation was much smaller. The quarantine, which required inspections and spraying, was triggered by two moths.

"It was never considered much more than a potential of a threat," viniculture consultant Prudy Foxx said.

Still, she said, everyone involved was happy to jump on it.

"Everybody had the same goal," Foxx said. "We didn't want to see that pest explode."

Fortunately, she said, vineyards were able to use an organic spray to combat the moth, though the five or six most affected by the quarantine incurred extra expense.

Growers also took care to process imported grapes quickly and dispose of waste carefully, measures that remain in effect, Nicoletti said.

Backyard vineyards were a concern for the commercial growers, but Nicoletti said residents complied with a federal mandate to either turn over their grapes or submit to a free treatment program.

The county's wine grape crop was valued at $1.6 million in 2011, the most recent figure available.